<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>CSS选择器语法</title>
</head>
<body>
    <div id="div1">
        <p id='p'>p1</p>
        <span id="sp3" class="ac span de">span</span>
    </div>
    <div id="div2">
        <p id='p'>p2</p>
        <a href="a2" class="ac">a2</a>
        <span id="sp2" class="ac">sp</span>
    </div>
</body>
</html>